EVANSTON, Ill. (CBS) - Adult content and maybe graphic pictures are to be expected for a human sexuality course, but at Northwestern University recently, more than 100 students watched a live sex demonstration.

According to our news partneres at CBS 2 in Chicago, a few weeks ago, Professor John Michael Bailey brought in a guest speaker for an optional demonstration after class. The students who attended ended up seeing a woman lying onstage, in person, being penetrated by a motorized sex toy.

The guest speaker behind the Feb. 21 demonstration was Ken Melvoin-Berg, who is known locally for his weird Chicago tours, and his courses at the Discovery Center on Lincoln Avenue , which include "Bondage for Beginners" and "Networking for Kinky People."

At his appearance for the Northwestern class, Melvoin-Berg said, "We brought a variety of tools with us that we actually use in our personal lifestyle, including a sex saw."

Melvoin-Berg said the students who stayed after class were informed of the graphic content over a dozen times, and received more warnings before a man used the sex saw on his fiancée in the live demonstration.

"(The woman) got on stage and took her pants and her panties off. She lay down on the stage and put a towel underneath her," Melvoin-Berg said. "Then (the man) plugged saw in. He brought her to orgasm right there on stage. That was the end of it, other than the fact that we had positive comments from everybody in the class."

But an angry Northwestern parent who called CBS 2 wasn't happy about the demonstration. She questions it's educational value, and wants professor Bailey fired.

Not all students endorse the demo either.

"I wouldn't feel like I would want to see that," one student said.

But Melvoin-Berg denies that the demonstration in any way amounted to "porn," as some have charged.

"These were all psychology students, and eventually they may be involved with people that are in sexual subcommunities," he said.

In an e-mail, Northwestern defended the class and its professor.

"Northwestern University faculty members engage in teaching and research on a wide variety of topics, some of them controversial and at the leading edge of their respective disciplines," said spokesman Alan Cubbage. "The University supports the efforts of its faculty to further the advancement of knowledge."

Bailey also released a statement Wednesday. He pointed out that the demonstration was "entirely optional" and was not covered on exams.

When Melvoin-Berg proposed the live demonstration, Bailey said he was only briefly hesitant, knowing that many students would find it "inappropriate."

"My decision to say 'yes' reflected my inability to come up with a legitimate reason why students should not be able to watch such a demonstration. After all, those still there had stayed for an optional demonstration/lecture about kinky sex, and were told explicitly what they were about to see," he said.

He echoed Melvoin-Berg's in calling reaction to the demonstration "uniformly positive."

Bill Yarber, a researcher at Indiana University's Kinsey Institute and author of the widely used textbook "Human Sexuality: Diversity in Contemporary America," said he's never heard of a naked woman being brought to orgasm in front of a class of students.